Apparatus for circulating drilling fluids



9 N. w. THOMPSON I ,252,050

APPARATUS FOR CIRCULATING DRILLING FLUIDS Filed Sept. 50, 1939 2 Sheets-Sheet 1 lnvenror: Nelson W. Thompson Aug. 12, 1941. N. w, THOMPSON 2,252,050

APPARATUS FOR CIRCULATING DRILLING FLUIDS Filed Sept. 30, 1939 2 Sheets-Sheet 2 4 his WQQ QM Patentedl Aug, l2, twill OFFICE 2,252,050 APPARATUS roa orncprlarnvo DRILLING rrlprns I t Nelson W. Thompson, Uakland, Caliii, assignor to Shell mevelopment Company, Caliil, a corporation of Delaware SanrFranciscn,

Application September 30,1939, SerialNo. 297,328 1 1 Claim.

down the drill pipe, out through the drill bit, and

backup through the casing (or in the opposite rig and a drilling fluid circulating system.

, FigureII is an enlarged vertical sectional view of a portion of the drilling fluid circulation system of the present invention.

-- Figure III is a cross-sectional view along the line III-III of FigureII I 1 Referring to Figure I of the drawings, drilling fiuidis withdrawn from the suction pit I through suction line .2 into valved flow-directing devices or casings 3 and 3a and forced out ofsaid devices direction in so-called reverse circulation dril1- by means of oscillating columns of liquid in uping), in order to carry drill bit cuttings to the right pipes 4 and 4a connected to a pump 5 as surface and to prevent wells traversing high hereinafter will be more fully described. The pressure strata from blowingout. pipes 4 and 4a communicate between said de- Reciprocating pumps of the piston or plunger vices and the piston or plunger pump 5, disposed type are commonly used to circulate the drilling ,15 at a considerablyhigher level than said devices fluid between its source of supplyand the well. and having; associated therewith reciprocating Due, however, tothe strongly abrasive action of prime-mover means, such as diagrammatically particles of clay, Weighting materials and ground shown at 6. The prime-mover .6 may be of any cuttings in the drilling fluid, thecylinders of said suitable type and, for. example, when operatively pumps soon become heavily scored, and, ihparassociated withtwo piston cylinders, it maybe "ticular, the packing on said pump cylinders and of the duplex double acting type. Therecipropistons is rapidly disintegrated, making it imcation of the piston 20 by means of the piston possible to maintain the desired pressures and rod 2 l causes liquid in the cylinder 5 and in the necessitating costly shut downs and repairs. upright pipes 4 and 4a connected near each end c It is, therefore, an object .of this invention to thereto and on opposite sides of the piston 20 to provide a drilling fluid circulation system in be oscillated, that is alternately displaced in opwhich a column of non-abrasive fluid, such as posite' direction. However, it is understood that clean oil, is interposed between the pump and I any other suitable means for oscillating a column the conduit conveying the drilling fluid from its of liquid in .anupright pipe will suffice for the sourceof supply to the well head, thereby pre; purposeof the present invention. I venting scoring of the pump and deterioration The oscillating columns in pipes 4 and 4a cause of the packing. the drilling fluid to be forced from thedevices 3 c It is also an object of this invention to provide and 3a through pressure line I to the flexible a drilling fluid circulation system comprising hose 8, through the swivel 9 and down they drill valved flow-directing devices located at a c0nsid- 5 stem ll, which is driven by the rotary table II). erably lower level than the drilling fluid pump, After passing out of the drill bit l2, the drilling wherebyanon-abrasive fluid may be maintained fluid with suspended drill bit cuttingsflows up- I in the pump and in the conduits between said Wards through the borehole l3 ,out through the pump and said devices above the drilling fluid surface casing l4 through line l5 to a vibrating filling the rest of the system and having a greater 401 screen i 8 for removal of the cuttings and is then specific gravity than said non-abrasive fluid.- discharged through line I! into the suction pit I. It is also an object of this invention to provide Now referring to the more detailed Figures II adrilling fluid circulatingsystem wherein floatand III of the pumping system, the lowerlend lng means having a specific gravity greater than of the upright pipe 4 may be provided with a the non-abrasivefluid filling on portion, of the valved drain line 22 and is connected, preferably, circulating system and less than the drilling fluid by means of a U-bend 30, to the lower portion filling the remaining portion of the circulating of a passage 3| in a preferred embodiment of the system is interposed at the interface between said valved flow-controlling device or casing 3. Lotwo fluids to prevent their becoming intercated above the passage 3 is a P es ur Cham ming1ed her 32, and located below the pump passage 3| is Further objects and advantages will be appara suction chamber 33. A cover 34 closes the top ent from the following description taken with of the pressure chamber 32 and a cover 35 closes reference to the drawings, wherein: an opening 36 in the upper wall of the pump pas- Figure I is a diagrammatic view of a drilling sage 3|, which is over the suction chamber 33.

An opening, 31, preferably fitted with a removforces the oil in Opening 50 provided with flange and opening 52 with flange 53 are provided in the pressure chamber 32 and the suction chamber 33, respectively, and are connected to the pressure line I and thesuction line 2, respectively.

The operation of the above-described embodiment of the present invention is as follows: .,-The entire interior of the pump passage 3|, the

pipes 4 and 4a are filled with drilling fluid which may conveniently be accomplished by feeding drilling fluid under slight pressure through the suction line 2. The upperportions of the pipes 4 and 4a and the entire interior of the pump cylinder 5 are filled with a suitable fluid, preferably non-abrasive, such as clean oil or other fluid preferably immiscible'with and having a specific gravity less than the drilling fluid which it is desired to circulate. The piston'rod 2| and piston 20 attached thereto are then reciprocatedby means of the prime-mover 6. This causes the contents of each end of the cylinder 5 to be alternately diminished: and increased and thereby and cutof the upright'pipes 4 and 4a, which in turn forces the drilling fluid in the lower portion of the pipes 4 and 4a and U- bends 30 in and out of the pump passage 3|. Thus, the suction, stroke'for the fluid in pipe 4 is the pressure stroke for the fluid in pipe 4a and, for example, when the interface between the oil and drilling fluid is at A in pipe 4, the interface aU-bends 3D, and about half way up the upright is at A in pipe 4a'; the positions of the interfaces changing to points B piston 20. 1

This oscillating motion of the liquid column in pipes 4 and 4a is transmitted to the pump passages 3| of the valve bodies 3 and 3a. Hence, for example on the suction stroke, that is movement on the reverse stroke of the of the liquid interface towards position A in pipe 4, a vacuum is caused in the pump passage 3| so that drilling fluid from the suction chamber 33-is drawn into the passage 3| through the opening 39, the valve42 lifting from its seat 40 against te spring 43 to allow this. On the'pressure stroke, that is, movement of the liquid interface to position B, the valve 42 forced by spring 43 into its seat 40, closing the opening 39, and drilling fluid in the pump passage 3| is forced into the pressure chamber 32, through the opening 31, the valve 4| lifting from its seat 38 to allow this. Thus, the oscillating motion of the column of oil causes drilling fluid to be drawn from thesuction pit I through the suction line 2 and suction manifold into the passage 3| and to be forced from said passage 3| into the pressure manifold and pressure line I and on into the well and then back to the pit I. I

Although the oil in the upper portion of the pipes 4 and 4a is generally prevented from mixing with the drilling fluid in contact therewith due to the difference in specific gravity, mixing may further be avoided by inserting a floating ball or piston 45 of a specific gravity greater than that of the non-abrasive liquid and. less than that of the drilling fluid at the interface of said fluids in the pipes 4 and 4a.

Particular importance is attached to ture of the upright pipes 4 and 40. being connected through a U-band to the lowermostportion of the pump passage 3| as this arrangement tends to prevent gas from getting into the cylinders 5, which would cut down the capacity and efliciency of the pump.

v It is likewise preferable that the height of the upright pipes 4 and 4a be such as to have a volume about twice that of the, volume of the piston cylinder in order to avoid the possibility of clean oil being forced around the U-bends 30 into the passage 3| and being mixed with the drilling fluid.

I claim as my invention:

In a, drilling fluid circulation system comprising conduit means between a supply 'of drilling fluid and the well head, two one-way valves in said conduit permittingfluid flow from said supply to said well head, a r'eciprocatingpump disposed at a higher level than said valves, a second conduit in fluid communication between said pump and said first conduit at a point intermediate said, two valves, a substantial portion of said second conduit extending-in a vertical direction, said pump and. a portion of the second condultadjacent said pump being filled with a NELSON W. THOMPSON.

the feaar n b v 

